1. Field of the Invention
The present invention relates to an optical apparatus, and more particularly, to an optical path control device for controlling the direction of light.
2. Description of the Related Art
One type of technology, important in everyday lives of humans, is optical technology. Many products which apply optical technology include, for example, LCD TVs, PDP TVs, and laser TVs. Optical path control is an important challenge in optical projection.
In existing optical path control area, U.S. Pat. No. 6,509,996 discloses an optical path control device. The optical path control device includes a flat mirror on an output axle of a servo motor to provide light, for example a laser, for reflection thereon. The servo motor rotates the flat mirror to change the incident angle of light reflected thereon.
The optical path control device further includes an angle sensor for detecting and reporting the angle state of the flat mirror to a servo circuit controlling the servo motor. Thus, the servo circuit may precisely control the servo motor to ensure that the flat mirror has an exact angle position. However, design of the above optical path control device is complex and fabrication costs are high.
Furthermore, a servo motor rotates clockwise or counter-clockwise at a predetermined angle to make the flat mirror suddenly arrive a predetermined position. Thus, the servo motor is suddenly started or stopped, resulting in vibration. Vibration decreases the light projection efficiency of the flat mirror applying the optical path control device.
According to requirement of the optical path control, in some embodiments, an incident light is reflected a few times at a constant angle. For example, the incident light, a laser, is reflected repeatedly and regularly at two different angles. According to the above requirement, to use the optical path control device brings high fabrication costs and poor reflection efficiency.